This invention relates to a power driven hair clipper.
A power driven hair clipper of the type initially referred to is known from U.S. Pat. No. 2,741,026. The cutting head, formed by an outer blade and an inner cutting blade driven to oscillate, is rigidly fastened to the yoke arms of the casing head constructed in a U-shaped configuration. The arcuate shape of the outer blade with its two rows of cutting teeth permits the hair clipper and the outer blade fastened thereto to execute a restricted pivot movement of 9xc2x0, while the relatively large distance of the cutting head""s row of teeth used at a time to the biggest diameter of the hair clipper""s casing is intended to enable both rows of teeth to be used for trimming purposes.
A power driven hair clipper is further known from U.S. Pat. No. 1,997,096, having a cutter head mounted for pivotal motion into corresponding positions for shaving and trimming, comprising a supporting element mounted for controlled pivotal motion along a curved track, a comb plate with only one row of teeth, and a cutter blade held in engagement with the comb plate by means of a resilient tension plate resting on the supporting element. An actuating element extending from the upper end of the casing transmits the driving motion to the cutter blade. A friction element acted upon by a spring element is arranged in the supporting element in such a way that it is urged against the upper surface of the hair clipper""s casing in order to hold the cutter head in any given pivot position by frictional pressure engagement. For the cutter head to be displaceable from its position of adjustment, the predetermined frictional force has to be overcome. This can lead during clipper operation to undesirable changes of position, especially since frictional forces tend to decrease in the course of using the hair clipper.
From GB-A-2 294 230 there is known a power driven hair clipper with a cutter head mounted for pivotal motion in all directions, whose pivotability is assured by a ball and socket connection between the housing and the cutter head. The cutter head, comprised of a supporting element and a housing cover member, includes a pair of blades, each equipped with two rows of cutting teeth extending parallel to each other but arranged in the cutter head in such a way that only one of the cooperating rows of cutting teeth on the pair of blades projects out of the cutter head housing. For the second row of cutting teeth to be brought into use, the cutter head has to be opened to enable the pair of blades to be turned through 180xc2x0 inside the cutter head.
From PCT-WO 98/47673 there is known a clipper head for a power driven hair clipper, comprising a supporting element, a clipper comb fastened thereto, and a clipper blade urged into engagement with the clipper comb via a driving element arranged to oscillate, under the action of a spring element bearing against the supporting element. A coupling element for transmitting the movement from the drive mechanism of the hair clipper to the clipper blade is provided on the driving element. To reduce the friction between the clipper comb and the clipper blade provision is made between the ends of the clipper comb and the clipper blade on the side remote from the row of cutting teeth for a friction-reducing component which is attached to the reciprocating clipper blade and is hence likewise set in reciprocating motion. For cleaning and replacement purposes, the supporting element of the clipper head is attachable to the housing by means of a clip connection.
It is an object of the present invention to improve in a power driven hair clipper of the type initially referred to the sliding ability of the reciprocating clipper blade relative to the clipper comb.
According to the invention this object is accomplished in a power driven hair clipper of the type initially referred to with the features identified here in.
According to the invention the clipper blade has its row of cutting teeth in engagement with the row of cutting teeth of the clipper comb while its engagement surface opposite its row of cutting teeth engages the foil, thereby producing a slightly in-clined position of the clipper blade to the clipper comb. This has as initial result that the sliding surface and consequently also the sliding surface of the clipper blade on the clipper comb, which is exposed to adhesive forces, is minimized. Furthermore, on account of the relatively narrow area with which the clipper blade makes engagement with the foil, the occurring sliding friction of the clipper blade with the opposed bearing surface formed by the foil is minimized. In a preferred embodiment of the invention the foil is fastened to the clipper comb and accordingly immovably arranged in the clipper head.
One embodiment of the invention is characterized in that the foil is fastened to the clipper comb by means of a chassis.
One significant advantage of the invention is afforded in that engagement of the engagement surface of the clipper blade with the foil enables an inclined position of the clipper blade relative to the row of cutting teeth to be obtained. Owing to this arrangement the surface adhesion occurring in cases where plane surfaces are in relative engagement is minimized by the attendant reduction in surfaces sliding relative to each other.
In a preferred embodiment of the invention at least one side of the foil is provided with a recessed surface structure. In a further aspect of this embodiment the recesses are constructed as holes passing through the foil. An alternative embodiment of the invention is characterized in that the recesses are constructed as blind-end bores. In another embodiment of the invention the recesses are formed by bars. In yet another advantageous embodiment of the invention the recesses are formed by holes and bars. To reduce the friction between the clipper blade and the foil still further, a greatly advantageous embodiment of the invention provides for the presence of a lubricant in the recesses. The recesses in the foil constitute lubricant depots with long-lasting effect.
According to another embodiment of the invention the surface structure of the foil is manufacturable by electroforming. This may take place, for example, in conjunction with an electroforming process of the foil as such. In still another embodiment of the invention the surface structure is manufacturable by an embossing process. A further embodiment of the invention is characterized in that the foil is formed of a plastics material. In an alternative embodiment the foil is made of a metal.
An embodiment of the present invention will be described in the following with reference to the accompanying drawings.